Semiconductor nanowires are becoming a major research focus in nanotechnology. Various methods of forming metal-oxide-semiconductor field-effect transistors (MOSFETs) comprising nanowires have been explored, including the use of dual material nanowire, where different material nanowires are used for N-channel field-effect transistor (NFET) and P-channel field-effect transistor (PFET) devices. For example, silicon (Si) nanowires may be used as the channel material for the NFET devices, while silicon germanium (SiGe) nanowires may be used as the channel material for the PFET devices. As another example, multiple-stacked (“multi-stack”) nanowires have been used in forming NFET and PFET devices, having the advantage of increasing the current carrying capability of these devices.